Shell Programming and Scripting

 
#!/bin/bash

# (Change to your path to photos)   
 
Pictures='/home/josh/Pictures'       

## Pick new image function
pick_new_bg () {
    backgrounds=( $( < ~/.background_temp) )
    num_backgrounds=${#backgrounds[*]}
    New=$(echo -n "${backgrounds[$((RANDOM%num_backgrounds))]}")    
}

## Get and export the DBUS_SESSION_BUS_ADDRESS for crontab compatibility
nautilus_pid=$(pgrep -u $LOGNAME -n nautilus)
eval $(tr '\0' '\n' < /proc/$nautilus_pid/environ | grep '^DBUS_SESSION_BUS_ADDRESS=')
export DBUS_SESSION_BUS_ADDRESS

## Find image titles in specified directory
ls $Pictures | egrep -i ".jpg|.png" > ~/.background_temp

## Pick new background image
pick_new_bg

## Get file name of current background and ensure the new background is different
Current=$(/usr/bin/gconftool-2 --get /desktop/gnome/background/picture_filename | xargs basename)

while [ $New == $Current ]
do
    pick_new_bg
done
## Set the new background and remove the temp file
/usr/bin/gconftool-2 --type string --set /desktop/gnome/background/picture_filename $Pictures/$New

rm ~/.background_temp